I filled up Friday on the way home from work for the first time to measure mileage. It was only a half tank and I'm quite sure it was a short fill (gas gauge doesn't read totally full). The SG said I should be in the low 50s, but I also used it while troubleshooting the Civic issues, so that threw it off. So, I think I'm just going to combine its data with the next fill when I get to that. I had 223.5 miles, 3.04 gallons for 73.5 mpg.
Today was a very nice commute considering it was only 7F out. Thankfully, the Metro was garage kept over the weekend, and the garage was 24F. So, it started out a fair amount warmer. But, traffic was light and I was able to get some good coasts in. The SG showed me 65.6 mpg in to work this morning, and I even got up to 180F by the time I got to work (yay grill block).
No real heat was used except leaving the vent on fresh air, hot heat setting, and putting it on defrost.